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Up to date with Rolls-Royce Bristol
Last week the Rolls-Royce Bristol/Snecma Olympus 593 Mk 602/610 of the Concorde became the world's first
supersonic passenger engine to pass a formal 150hr Type Approval test. In production on the same shop floor,
and representing another unique world aero-engine achievement, is the Harrier's Pegasus. Rolls-Royce Bristol
is also developing, with the Germans and Italians in Turbo Union, the most advanced combat engine in Europe,
the RB.199 for the MRCA. The M45H civil turbofan is in development and production for the VFW-Fokker 614;
and projects to quieten and eventually to replace the Viper are in hand. J. M. RAMSDEN reports from Bristol
DESPITE the constant temptation and opportunity to improve the Olympus, and especially to launch the Mk 622, Rolls-Royce Rristol feels strongly that the
priority is to get the Mk 610-engined Concorde into passen
ger service as quickly as possible.
The British company and its French partner Snecma
will deliver passenger-certificated Mk 610 engines some 18
months ahead of Concorde's present in-service target date.
But as Rolls-Royce Bristol engineers point out, what matters
is certification of the integrated Concorde powerplant;
there is no short cut to 500hr of in-flight endurance testing
required by the British CAA and French SGAC.
Rolls-Royce Rristol believes that it speaks for all the
contractors in advocating earliest passenger service—to
prove that the Atlantic in half the time is a saleable com
modity. If it is, then the supersonic airliner is saleable
whether it is modified to carry x per cent more payload or
i ot.
Further sales now depend on testing the market. Pas
senger operation is essential also to evaluate reactions to
airport noise and boom, and to see what the passenger
will actually pay for halved journey times.
Not least important for the contractors is the question
of their employees' enthusiasm and morale. This can get
difficult to maintain if, after 12 years' work, there seems
to be one change of plan after another.
The Olympus programme is still tight. One of the bottle
necks could be the TRA nozzles, which are a Snecma
responsibility. The French company is discussing with the
American supplier the delivery date, manufacturing guaran
tees and prices of the stainless-steel honeycomb used for
these reversers.
Three aircraft are flying with the TRA nozzles—02, 201
and 202. There are no intractable problems technically,
although components of the fourth TRA nozzle/reverser
are still the subject of acceptance discussions with the
US manufacturer.
Another reason for getting Concorde into service as
quickly as possible is the changing social and political
climate in which aircraft noise is judged. If Concorde had
gone into service in 1970, as originally planned, the relative
noisiness of the narrow-body subsonic jets would have
made the supersonic airliner more acceptable. This is
why, while giving priority to the earliest in-service date
of the Olympus 610-powered aircraft, Rolls-Royce Bristol
and Snecma are advocating development of the Mk 622.
The proposed Olympus Mk 622 has a higher mass flow
thanks to a slightly bigger compressor—l^in greate n
diameter—and a slower jet velocity. Mass flow is about
8 per cent higher and thrust between 7 and 8 per cent above
the existing Mk 610 take-off rating. The demonstrator
compressor has been built and is on test.
For the demonstrator three new stages have been added
to a "sawn-off" front of a standard Mk 602. Though only a
minimum-cost improvisation, it is demonstrating the esti
mated increases in mass flow and thrust. The Mk 622's
intake would be basically the same. Flight-testing to check
nacelle aerodynamics and to build up hours would be
required. The Mk 622 would also require minor nacelle
changes but it would be "retrofittable" to the Al Concorde
and without major alterations to the first Concorde As.
The Mk 622's lower jet velocity would help sideline noise
but take-off would be noticeably less noisy thanks to the
greater thrust and hence climb-out angle (this would also be
improved by the higher wing lift of the R Concorde, to
which the Mk 622 engine would be fitted).
Another argument for getting on with the Mk 622 is
that it is a "new ladder" leading to higher thrust. Not to
get on to it—excluding the first aircraft—must be con
trary to all aviation experience.
Cost of developing the Mk 622 is not defined, but would
probably be £40 million up to passenger certification. The
engine manufacturers consider that the social pressure
to reduce airport noise makes the Mk 622 an essential